



Are bases of DNA molecule. As DNA contain four bases, which are adenine, guanine, cytosine and thymine.
A DNA molecule is composed of four different nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Each of these bases has a unique chemical structure that contributes to the double helix formation of DNA. The question asks us to identify the incorrect base structure among the given options. Let us examine each base:
The correct base structures of the DNA are well-defined:
By evaluating the structures provided in the options, we can identify the one that does not match the structure of any of these standard bases. The incorrect structure here is option 3, which does not correspond to the correct chemical structure of any standard DNA bases.
In conclusion, the incorrect base structure in the question is the one depicted in option 3. Make sure to remember key characteristics of purines and pyrimidines while evaluating such diagrams in exams.
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.